This invention relates to a catalyst containing thorium oxide and at least one Group VIII transition metal, such as nickel, cobalt or iron thorium oxide.
The transition metals of Group VIII of the Periodic Table have long been known for their catalytic activity when prepared in a finely divided or high surface area form. Nickel in particular has found extensive use as a catalyst in hydrogenation and methanation reactions. A number of standard techniques to obtain high surface area metal catalysts have been developed. Illustrative of these are impregnation, precipitation, ion-exchange, Raney metal and reduction of the fused oxide. Since reactions which are promoted with a catalyst usually occur on the surface of the catalyst through adsorption of one or more of the reactants, it is usually desirable to obtain catalysts with the largest active surface area practicable.
Another technique which is useful to prepare catalysts from an alloy of a Group VIII transition metal and yttrium or a rare earth metal is described in U.S. Pat. No. 4,071,473, issued on Jan. 31, 1978. This process includes an activation step which involves further treatment of a material prepared by treating an alloy at elevated temperature in a hydrogen-carbon monoxide gas mixture. In the further treatment step the same reactive gas mixture may be used but at a lower temperature. The disclosure of U.S. Pat. No. 4,071,473 is herein incorporated by reference. That process has further been extended to metals other than yttrium and rare earth metals as disclosed in our co-pending application Ser. No. 162,542, filed June 24, 1980, the disclosure of which is hereby incorporated by reference. While the process just referred to produces an excellent catalyst, it has now been found that a catalyst of thorium oxide and at least one Group VIII transition metal can be prepared from an alloy by a simple oxidation procedure in air followed by reduction of the transition metal oxide.